• SpringBoot视图渲染技术

    目录

    一、Freemarker入门

    二、Freemarker的基本语法

    三、Freemarker综合案例

    实现步骤：

    1、entity、Mapper.java、Mapper.xml、biz、Controller

    2、jsp——>freemarker

    3、jsp中是有分页标签 ——> freemarker中的分页条展示问题，以及分页功能

    4、整合aop PageHelper插件

    后端处理：

    前端页面处理：

    一、Freemarker入门

    SpringBoot默认是不推荐使用jsp的，本身就是向前端推送数据。

    学习网址：

http://freemarker.foofun.cn/

    项目创建如下：

    六个组件 —

     生成后相关配置稍作调整

    yml文件：

    1. mybatis:
    2.     mapper-locations: classpath:mappers/*xml
    3.     type-aliases-package: com.ycx.spboot04.mybatis.model
    4. server:
    5.     port: 8080
    6. spring:
    7.     application:
    8.         name: spboot04
    9.     datasource:
    10.         driver-class-name: com.mysql.jdbc.Driver
    11.         name: defaultDataSource
    12.         password: 123456
    13.         url: jdbc:mysql://localhost:3306/yjy?useUnicode=true&characterEncoding=UTF-8
    14.         username: root
    15.     freemarker:
    16.         cache: false
    17.         charset: utf-8
    18.         expose-request-attributes: true
    19.         expose-session-attributes: true
    20.         suffix: .ftl
    21.         template-loader-path: classpath:/templates/
    22. #    resources:
    23. #        static-locations: classpath:/static/# 应用服务 WEB 访问端口
    24.     mvc:
    25.         static-path-pattern: classpath:/static/

     接着：

     

     

     

     index.ftl

    1. DOCTYPE html>
    2. <html lang="en">
    3. <head>
    4.     <meta charset="UTF-8">
    5.     <title>title>
    6. head>
    7. <body>
    8. 欢迎来到 Freemarker首页！
    9. body>
    10. html>

    controllerIndexController :

    1. package com.ycx.spboot04.contrller;
    2.  
    3. import org.springframework.stereotype.Controller;
    4. import org.springframework.web.bind.annotation.RequestMapping;
    5.  
    6. /**
    7.  * @author 杨总
    8.  * @create 2022-11-02 1:12
    9.  */
    10. @Controller
    11. @RequestMapping
    12. public class IndexController {
    13.     @RequestMapping("/")
    14.     public String index(){
    15.         System.out.println("come in...");
    16.         return "index";
    17.     }
    18. }

    测试：

    二、Freemarker的基本语法

    1. html>
    2. <html lang="en">
    3. <head>
    4.     <meta charset="UTF-8">
    5.     <title>title>
    6. head>
    7. <body>
    8. <h2>1.取值h2>
    9. <h3>1.1. 提供默认值h3>
    10. <#--报错-->
    11. <#--${uname}    -->
    12. <#--不报错，但是页面无内容-->
    13. <#--${uname !}-->
    14. <#--给值设置一个默认值-->
    15. ${uname! '无名'}
    16.  
    17. <h3>1.2. 对null值先进行判断h3>
    18. <p>1）exists用在逻辑判断；p>
    19. <#if uname?exists>
    20.     ${uname}
    22. <br>
    23. <p>2）??是判断对象是否为空p>
    24. <#if uname??>
    25.     ${uname}
    27. <br>
    28. <p>3）if_exists用来打印东西p>
    29. ${uname?if_exists}
    30. <br>
    31.  
    32. <h3>2.条件h3>
    33. <#if sex=='nv'>
    34.     女
    35. <#elseif sex='nan'>
    36.     男
    37. <#else>
    38.     未知
    40. <br>
    41.  
    42.  
    43. <h3>3.循环h3>
    44. <p>1）取出数组中的元素p>
    45. <#list arr as a>
    46.     ${a}==
    48. <br>
    49. <p>2）取出集合中的对象（注：访问的类要被public所修饰）p>
    50. <#list lst as item>
    51.     ${item.id} : ${item.name}    <br>
    53.  
    54. <h3>4 includeh3>
    55. <#include "/common.ftl" >
    56.  
    57. <h3>5 局部变量(assign)/全局变量(global)h3>
    58. ${ctx}：${ctx2}
    59. body>
    60. html>

     common.ftl

    1. <#assign ctx>
    2.     ${springMacroRequestContext.contextPath}
    4. <#global ctx2>
    5.     ${springMacroRequestContext.contextPath}

    IndexController ：

    1. package com.ycx.spboot04.controller;
    2.  
    3. import com.ycx.spboot04.entity.User;
    4. import org.springframework.stereotype.Controller;
    5. import org.springframework.ui.Model;
    6. import org.springframework.web.bind.annotation.GetMapping;
    7.  
    8. import java.util.ArrayList;
    9. import java.util.List;
    10.  
    11. /**
    12.  * @author杨总
    13.  * 
    14.  */
    15. @Controller
    16. public class IndexController {
    17.     @GetMapping("/")
    18.     public String index(Model model) {
    19.         System.out.println("come in............");
    20.         model.addAttribute("uname", "小刘");
    21.         model.addAttribute("sex", "girl");
    22.         List<User> lst = new ArrayList<>();
    23.         lst.add(new User(1, "zs"));
    24.         lst.add(new User(2, "ls"));
    25.         lst.add(new User(3, "ww"));
    26.  
    27.         model.addAttribute("lst",lst);
    28.         model.addAttribute("arr", new Integer[]{5, 6, 7, 8, 9});
    29.         return "index";
    30.     }
    31. }

    三、Freemarker综合案例

    利用Freemarker完成基本的增删改查，参照之前ssm项目进行改造

    实现步骤：

    1、entity、Mapper.java、Mapper.xml、biz、Controller

    2、jsp——>freemarker

    3、jsp中是有分页标签 ——> freemarker中的分页条展示问题，以及分页功能

    4、整合aop PageHelper插件

    后端处理：

    SpringBoot aop整合分页，添加配置如下：


          org.springframework
          spring-aspects
          5.0.2.RELEASE
       
        
       
           com.github.pagehelper
           pagehelper-spring-boot-starter
           1.2.3
              

    完整版依赖： 

    1. "1.0" encoding="UTF-8"?>
    2. <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    3.          xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    4.     <modelVersion>4.0.0modelVersion>
    5.     <groupId>com.ycxgroupId>
    6.     <artifactId>spboot04artifactId>
    7.     <version>0.0.1-SNAPSHOTversion>
    8.     <name>spboot04name>
    9.     <description>Demo project for Spring Bootdescription>
    10.  
    11.     <properties>
    12.         <java.version>1.8java.version>
    13.         <project.build.sourceEncoding>UTF-8project.build.sourceEncoding>
    14.         <project.reporting.outputEncoding>UTF-8project.reporting.outputEncoding>
    15.         <spring-boot.version>2.3.7.RELEASEspring-boot.version>
    16.     properties>
    17.  
    18.     <dependencies>
    19.         <dependency>
    20.             <groupId>org.springframework.bootgroupId>
    21.             <artifactId>spring-boot-starter-freemarkerartifactId>
    22.         dependency>
    23.         <dependency>
    24.             <groupId>org.springframework.bootgroupId>
    25.             <artifactId>spring-boot-starter-jdbcartifactId>
    26.         dependency>
    27.         <dependency>
    28.             <groupId>org.springframework.bootgroupId>
    29.             <artifactId>spring-boot-starter-webartifactId>
    30.         dependency>
    31.         <dependency>
    32.             <groupId>org.mybatis.spring.bootgroupId>
    33.             <artifactId>mybatis-spring-boot-starterartifactId>
    34.             <version>2.1.4version>
    35.         dependency>
    36.  
    37.         <dependency>
    38.             <groupId>mysqlgroupId>
    39.             <artifactId>mysql-connector-javaartifactId>
    40.             <version>5.1.44version>
    41.         dependency>
    42.  
    43.         
    44.         <dependency>
    45.             <groupId>org.springframeworkgroupId>
    46.             <artifactId>spring-aspectsartifactId>
    47.             <version>5.0.2.RELEASEversion>
    48.         dependency>
    49.         
    50.         <dependency>
    51.             <groupId>com.github.pagehelpergroupId>
    52.             <artifactId>pagehelper-spring-boot-starterartifactId>
    53.             <version>1.2.3version>
    54.         dependency>
    55.  
    56.         <dependency>
    57.             <groupId>org.projectlombokgroupId>
    58.             <artifactId>lombokartifactId>
    59.             <optional>trueoptional>
    60.         dependency>
    61.         <dependency>
    62.             <groupId>org.springframework.bootgroupId>
    63.             <artifactId>spring-boot-starter-testartifactId>
    64.             <scope>testscope>
    65.             <exclusions>
    66.                 <exclusion>
    67.                     <groupId>org.junit.vintagegroupId>
    68.                     <artifactId>junit-vintage-engineartifactId>
    69.                 exclusion>
    70.             exclusions>
    71.         dependency>
    72.     dependencies>
    73.  
    74.     <dependencyManagement>
    75.         <dependencies>
    76.             <dependency>
    77.                 <groupId>org.springframework.bootgroupId>
    78.                 <artifactId>spring-boot-dependenciesartifactId>
    79.                 <version>${spring-boot.version}version>
    80.                 <type>pomtype>
    81.                 <scope>importscope>
    82.             dependency>
    83.         dependencies>
    84.     dependencyManagement>
    85.  
    86.     <build>
    87.         <plugins>
    88.             <plugin>
    89.                 <groupId>org.apache.maven.pluginsgroupId>
    90.                 <artifactId>maven-compiler-pluginartifactId>
    91.                 <version>3.8.1version>
    92.                 <configuration>
    93.                     <source>1.8source>
    94.                     <target>1.8target>
    95.                     <encoding>UTF-8encoding>
    96.                 configuration>
    97.             plugin>
    98.             <plugin>
    99.                 <groupId>org.springframework.bootgroupId>
    100.                 <artifactId>spring-boot-maven-pluginartifactId>
    101.                 <version>2.3.7.RELEASEversion>
    102.                 <configuration>
    103.                     <mainClass>com.ycx.spboot04.Spboot04ApplicationmainClass>
    104.                 configuration>
    105.                 <executions>
    106.                     <execution>
    107.                         <id>repackageid>
    108.                         <goals>
    109.                             <goal>repackagegoal>
    110.                         goals>
    111.                     execution>
    112.                 executions>
    113.             plugin>
    114.         plugins>
    115.     build>
    116.  
    117. project>

    把如下配置加到yml文件中 

    pagehelper:
      reasonable: true
      supportMethodsArguments: true
      page-size-zero: true
      helper-dialect: mysql

    1. mybatis:
    2.     mapper-locations: classpath:mappers/*xml
    3.     type-aliases-package: com.ycx.spboot04.model
    4. server:
    5.     port: 8080
    6.     servlet:
    7.         context-path: /spboot04
    8. spring:
    9.     application:
    10.         name: spboot04
    11.     datasource:
    12.         driver-class-name: com.mysql.jdbc.Driver
    13.         name: defaultDataSource
    14.         password: 1234
    15.         url: jdbc:mysql://localhost:3306/yjy?useUnicode=true&characterEncoding=UTF-8
    16.         username: root
    17.     freemarker:
    18.         cache: false
    19.         charset: utf-8
    20.         expose-request-attributes: true
    21.         expose-session-attributes: true
    22.         suffix: .ftl
    23.         template-loader-path: classpath:/templates/
    24. #    resources:
    25. #        static-locations: classpath:/static/# 应用服务 WEB 访问端口
    26.     mvc:
    27.         static-path-pattern: classpath:/static/
    28.     pagehelper:
    29.         reasonable: true
    30.         supportMethodsArguments: true
    31.         page-size-zero: true
    32.         helper-dialect: mysql

    实体类Clazz.java：

    1. package com.ycx.spboot04.model;
    2.  
    3.  
    4. import java.io.Serializable;
    5.  
    6. /**
    7.  * NotNull:针对的是基本数据类型
    8.  *  @NotEmpty 作用于集合
    9.  *  @NotBlank    作用于字符串
    10.  */
    11.  
    12. public class Clazz implements Serializable {
    13.     protected Integer cid;
    14.  
    15.     protected String cname;
    16.  
    17.     protected String cteacher;
    18.  
    19.     protected String pic;
    20.  
    21.     public Clazz(Integer cid, String cname, String cteacher, String pic) {
    22.         this.cid = cid;
    23.         this.cname = cname;
    24.         this.cteacher = cteacher;
    25.         this.pic = pic;
    26.     }
    27.  
    28.     public Clazz() {
    29.         super();
    30.     }
    31.  
    32.     public Integer getCid() {
    33.         return cid;
    34.     }
    35.  
    36.     public void setCid(Integer cid) {
    37.         this.cid = cid;
    38.     }
    39.  
    40.     public String getCname() {
    41.         return cname;
    42.     }
    43.  
    44.     public void setCname(String cname) {
    45.         this.cname = cname;
    46.     }
    47.  
    48.     public String getCteacher() {
    49.         return cteacher;
    50.     }
    51.  
    52.     public void setCteacher(String cteacher) {
    53.         this.cteacher = cteacher;
    54.     }
    55.  
    56.     public String getPic() {
    57.         return pic;
    58.     }
    59.  
    60.     public void setPic(String pic) {
    61.         this.pic = pic;
    62.     }
    63. }

    ClazzBiz ：

    1. package com.ycx.spboot04.biz;
    2.  
    3. import com.ycx.spboot04.model.Clazz;
    4. import com.ycx.spboot04.util.PageBean;
    5. import org.springframework.cache.annotation.CacheEvict;
    6. import org.springframework.cache.annotation.CachePut;
    7.  
    8. import java.util.List;
    9. import java.util.Map;
    10.  
    11. public interface ClazzBiz {
    12.     @CacheEvict(value = "xx",key = "'cid:'+#cid",allEntries = true)
    13.     int deleteByPrimaryKey(Integer cid);
    14.  
    15.     int insert(Clazz record);
    16.  
    17.     int insertSelective(Clazz record);
    18.  
    19. //    xx=cache-cid:1
    20. //    key的作用改变原有的key生成规则
    21. //    @Cacheable(value = "xx",key = "'cid:'+#cid",condition = "#cid > 6")
    22.     @CachePut(value = "xx",key = "'cid:'+#cid",condition = "#cid > 6")
    23.     Clazz selectByPrimaryKey(Integer cid);
    24.  
    25.     int updateByPrimaryKeySelective(Clazz record);
    26.  
    27.     int updateByPrimaryKey(Clazz record);
    28.  
    29.     List<Clazz> listPager(Clazz clazz, PageBean pageBean);
    30.     List<Map> listMapPager(Clazz clazz, PageBean pageBean);
    31. }

    ClazzMapper.java:

    1. package com.ycx.spboot04.mapper;
    2.  
    3. import com.ycx.spboot04.model.Clazz;
    4. import org.springframework.stereotype.Repository;
    5.  
    6. import java.util.List;
    7. import java.util.Map;
    8.  
    9. @Repository
    10. public interface ClazzMapper {
    11.     int deleteByPrimaryKey(Integer cid);
    12.  
    13.     int insert(Clazz record);
    14.  
    15.     int insertSelective(Clazz record);
    16.  
    17.     Clazz selectByPrimaryKey(Integer cid);
    18.  
    19.     List<Clazz> listPager(Clazz clazz);
    20.  
    21.     List<Map> listMapPager(Clazz clazz);
    22.  
    23.     int updateByPrimaryKeySelective(Clazz record);
    24.  
    25.     int updateByPrimaryKey(Clazz record);
    26. }

    ClazzBizImpl.java:

    1. package com.ycx.spboot04.biz.impl;
    2.  
    3. import com.ycx.spboot04.biz.ClazzBiz;
    4. import com.ycx.spboot04.mapper.ClazzMapper;
    5. import com.ycx.spboot04.model.Clazz;
    6. import com.ycx.spboot04.util.PageBean;
    7. import org.springframework.beans.factory.annotation.Autowired;
    8. import org.springframework.stereotype.Service;
    9.  
    10. import java.util.List;
    11. import java.util.Map;
    12.  
    13.  
    14. @Service
    15. public class ClazzBizImpl implements ClazzBiz {
    16.     @Autowired
    17.     private ClazzMapper clazzMapper;
    18.     @Override
    19.     public int deleteByPrimaryKey(Integer cid) {
    20.         System.out.println("不做任何操作...");
    21.       return clazzMapper.deleteByPrimaryKey(cid);
    22.   //        return 0;
    23.     }
    24.  
    25.     @Override
    26.     public int insert(Clazz record) {
    27.         return clazzMapper.insert(record);
    28.     }
    29.  
    30.     @Override
    31.     public int insertSelective(Clazz record) {
    32.         return clazzMapper.insertSelective(record);
    33.     }
    34.  
    35.     @Override
    36.     public Clazz selectByPrimaryKey(Integer cid) {
    37.         return clazzMapper.selectByPrimaryKey(cid);
    38.     }
    39.  
    40.     @Override
    41.     public int updateByPrimaryKeySelective(Clazz record) {
    42.         return clazzMapper.updateByPrimaryKeySelective(record);
    43.     }
    44.  
    45.     @Override
    46.     public int updateByPrimaryKey(Clazz record) {
    47.         return clazzMapper.updateByPrimaryKey(record);
    48.     }
    49.  
    50.     @Override
    51.     public List<Clazz> listPager(Clazz clazz, PageBean pageBean) {
    52.         return clazzMapper.listPager(clazz);
    53.     }
    54.  
    55.     @Override
    56.     public List<Map> listMapPager(Clazz clazz, PageBean pageBean) {
    57.         if(true)
    58.             throw new RuntimeException("查询班级信息异常，异常存在于ClazzBizImpl.list。。。。");
    59.         return clazzMapper.listMapPager(clazz);
    60.     }
    61. }

    ClazzMapper.xml：

    1. "1.0" encoding="UTF-8" ?>
    2. DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd" >
    3. <mapper namespace="com.ycx.spboot04.mapper.ClazzMapper" >
    4.   <resultMap id="BaseResultMap" type="Clazz" >
    5.     <constructor >
    6.       <idArg column="cid" jdbcType="INTEGER" javaType="java.lang.Integer" />
    7.       <arg column="cname" jdbcType="VARCHAR" javaType="java.lang.String" />
    8.       <arg column="cteacher" jdbcType="VARCHAR" javaType="java.lang.String" />
    9.       <arg column="pic" jdbcType="VARCHAR" javaType="java.lang.String" />
    10.     constructor>
    11.   resultMap>
    12.   <sql id="Base_Column_List" >
    13.     cid, cname, cteacher, pic
    14.   sql>
    15.   <select id="selectByPrimaryKey" resultMap="BaseResultMap" parameterType="java.lang.Integer" >
    16.     select 
    17.     <include refid="Base_Column_List" />
    18.     from t_struts_class
    19.     where cid = #{cid,jdbcType=INTEGER}
    20.   select>
    21.  
    22.   <select id="listMapPager" resultType="java.util.Map" parameterType="Clazz" >
    23.     select
    24.     <include refid="Base_Column_List" />
    25.     from t_struts_class
    26.     <where>
    27.       <if test="cname != null and cname != ''">
    28.          and cname like CONCAT('%',#{cname},'%')
    29.       if>
    30.       <if test="cid != null and cid != ''">
    31.         and cid = #{cid}
    32.       if>
    33.     where>
    34.   select>
    35.  
    36.   <select id="listPager" resultType="Clazz" parameterType="Clazz" >
    37.     select
    38.     <include refid="Base_Column_List" />
    39.     from t_struts_class
    40.     <where>
    41.       <if test="cname != null and cname != ''">
    42.         and cname like CONCAT('%',#{cname},'%')
    43.       if>
    44.       <if test="cid != null and cid != ''">
    45.         and cid = #{cid}
    46.       if>
    47.     where>
    48.   select>
    49.  
    50.   <delete id="deleteByPrimaryKey" parameterType="java.lang.Integer" >
    51.     delete from t_struts_class
    52.     where cid = #{cid,jdbcType=INTEGER}
    53.   delete>
    54.   <insert id="insert" parameterType="Clazz" >
    55.     insert into t_struts_class (cid, cname, cteacher, 
    56.       pic)
    57.     values (#{cid,jdbcType=INTEGER}, #{cname,jdbcType=VARCHAR}, #{cteacher,jdbcType=VARCHAR}, 
    58.       #{pic,jdbcType=VARCHAR})
    59.   insert>
    60.   <insert id="insertSelective" parameterType="Clazz" >
    61.     insert into t_struts_class
    62.     <trim prefix="(" suffix=")" suffixOverrides="," >
    63.       <if test="cid != null" >
    64.         cid,
    65.       if>
    66.       <if test="cname != null" >
    67.         cname,
    68.       if>
    69.       <if test="cteacher != null" >
    70.         cteacher,
    71.       if>
    72.       <if test="pic != null" >
    73.         pic,
    74.       if>
    75.     trim>
    76.     <trim prefix="values (" suffix=")" suffixOverrides="," >
    77.       <if test="cid != null" >
    78.         #{cid,jdbcType=INTEGER},
    79.       if>
    80.       <if test="cname != null" >
    81.         #{cname,jdbcType=VARCHAR},
    82.       if>
    83.       <if test="cteacher != null" >
    84.         #{cteacher,jdbcType=VARCHAR},
    85.       if>
    86.       <if test="pic != null" >
    87.         #{pic,jdbcType=VARCHAR},
    88.       if>
    89.     trim>
    90.   insert>
    91.   <update id="updateByPrimaryKeySelective" parameterType="Clazz" >
    92.     update t_struts_class
    93.     <set >
    94.       <if test="cname != null" >
    95.         cname = #{cname,jdbcType=VARCHAR},
    96.       if>
    97.       <if test="cteacher != null" >
    98.         cteacher = #{cteacher,jdbcType=VARCHAR},
    99.       if>
    100.       <if test="pic != null" >
    101.         pic = #{pic,jdbcType=VARCHAR},
    102.       if>
    103.     set>
    104.     where cid = #{cid,jdbcType=INTEGER}
    105.   update>
    106.   <update id="updateByPrimaryKey" parameterType="Clazz" >
    107.     update t_struts_class
    108.     set cname = #{cname,jdbcType=VARCHAR},
    109.       cteacher = #{cteacher,jdbcType=VARCHAR},
    110.       pic = #{pic,jdbcType=VARCHAR}
    111.     where cid = #{cid,jdbcType=INTEGER}
    112.   update>
    113. mapper>

    ClazzController.java：

    1. package com.ycx.spboot04.controller;
    2.  
    3. import com.ycx.spboot04.biz.ClazzBiz;
    4. import com.ycx.spboot04.model.Clazz;
    5. import com.ycx.spboot04.util.PageBean;
    6. import org.springframework.beans.factory.annotation.Autowired;
    7. import org.springframework.http.HttpHeaders;
    8. import org.springframework.http.HttpStatus;
    9. import org.springframework.http.MediaType;
    10. import org.springframework.http.ResponseEntity;
    11. import org.springframework.stereotype.Controller;
    12. import org.springframework.validation.BindingResult;
    13. import org.springframework.validation.FieldError;
    14. import org.springframework.web.bind.annotation.RequestMapping;
    15. import org.springframework.web.multipart.MultipartFile;
    16.  
    17. import javax.servlet.http.HttpServletRequest;
    18. import java.util.HashMap;
    19. import java.util.List;
    20. import java.util.Map;
    21.  
    22. /**
    23.  * @author杨总
    24.  */
    25. @Controller
    26. @RequestMapping("/clz")
    27. public class ClazzController {
    28.     @Autowired
    29.     private ClazzBiz clazzBiz;
    30. //    list->clzList
    31. //    toList->重定向list->"redirect:/clz/list"
    32. //    toEdit->跳转到编辑界面->clzEdit
    33. //    Clazz : 以前是通过模型驱动接口封装，现在是直接在方法中接受参数即可
    34.     @RequestMapping("/list")
    35.     public String list(Clazz clazz, HttpServletRequest request){
    36.         System.out.println("我添加了 新的代码,终于不重启了....");
    37.         PageBean pageBean = new PageBean();
    38.         pageBean.setRequest(request);
    39.         List<Clazz> lst = this.clazzBiz.listPager(clazz, pageBean);
    40.         request.setAttribute("lst",lst);
    41.         request.setAttribute("pageBean",pageBean);
    42.         return "clz/clzList";
    43.     }
    44.  
    45.     @RequestMapping("/toEdit")
    46.     public String toEdit(Clazz clazz, HttpServletRequest request){
    47.         Integer cid = clazz.getCid();
    48. //        传递的id代表了修改，没传代表新增
    49.         if(cid != null){
    50.             List<Clazz> lst = this.clazzBiz.listPager(clazz, null);
    51.             request.setAttribute("b",lst.get(0));
    52.         }
    53.         return "clz/clzEdit";
    54.     }
    55.  
    56.     @RequestMapping("/add")
    57.     public String add(Clazz clazz){
    58.         this.clazzBiz.insertSelective(clazz);
    59.         return "redirect:/clz/list";
    60.     }
    61.  
    62.  
    63.  
    64.  
    65.     @RequestMapping("/edit")
    66.     public String edit(Clazz clazz){
    67.         this.clazzBiz.updateByPrimaryKeySelective(clazz);
    68.         return "redirect:/clz/list";
    69.     }
    70.  
    71.     @RequestMapping("/del")
    72.     public String del(Clazz clazz){
    73.         this.clazzBiz.deleteByPrimaryKey(clazz.getCid());
    74.         return "redirect:/clz/list";
    75.     }
    76.  
    77.  
    78. }

    PagerAspect ：

    1. package com.ycx.spboot04.aspect;
    2.  
    3. import com.github.pagehelper.PageHelper;
    4. import com.github.pagehelper.PageInfo;
    5. import com.ycx.spboot04.util.PageBean;
    6. import org.aspectj.lang.ProceedingJoinPoint;
    7. import org.aspectj.lang.annotation.Around;
    8. import org.aspectj.lang.annotation.Aspect;
    9. import org.springframework.stereotype.Component;
    10.  
    11. import java.util.List;
    12.  
    13. @Component
    14. @Aspect
    15. public class PagerAspect {
    16.  
    17.     /**
    18.      * *：返回值类型
    19.      * *..：无限包
    20.      * *Service：以Service结尾接口名
    21.      * *Pager：以Pager方法
    22.      * 只要同时匹配上诉四个条件，就会被列为目标对象
    23.      * 上述配置要生效，代理注解不能少
    24.      * @param args
    25.      * @return
    26.      * @throws Throwable
    27.      */
    28.     @Around("execution(* *..*Biz.*Pager(..))")
    29.     public Object invoke(ProceedingJoinPoint args) throws Throwable {
    30.         Object[] params = args.getArgs();
    31.         PageBean pageBean = null;
    32.         for (Object param : params) {
    33.             if(param instanceof PageBean){
    34.                 pageBean = (PageBean)param;
    35.                 break;
    36.             }
    37.         }
    38.  
    39.         if(pageBean != null && pageBean.isPagination())
    40.             PageHelper.startPage(pageBean.getPage(),pageBean.getRows());
    41.  
    42. //        执行目标方法
    43.         Object list = args.proceed(params);
    44.  
    45.         if(null != pageBean && pageBean.isPagination()){
    46.             PageInfo pageInfo = new PageInfo((List) list);
    47.             pageBean.setTotal(pageInfo.getTotal()+"");
    48.         }
    49.         return list;
    50.     }
    51.  
    52.  
    53. }

    StringUtils ：

    1. package com.ycx.spboot04.util;
    2.  
    3. public class StringUtils {
    4. 	// 私有的构造方法，保护此类不能在外部实例化
    5. 	private StringUtils() {
    6. 	}
    7.  
    8. 	/**
    9. 	 * 如果字符串等于null或去空格后等于""，则返回true，否则返回false
    10. 	 * 
    11. 	 * @param s
    12. 	 * @return
    13. 	 */
    14. 	public static boolean isBlank(String s) {
    15. 		boolean b = false;
    16. 		if (null == s || s.trim().equals("")) {
    17. 			b = true;
    18. 		}
    19. 		return b;
    20. 	}
    21. 	
    22. 	/**
    23. 	 * 如果字符串不等于null或去空格后不等于""，则返回true，否则返回false
    24. 	 * 
    25. 	 * @param s
    26. 	 * @return
    27. 	 */
    28. 	public static boolean isNotBlank(String s) {
    29. 		return !isBlank(s);
    30. 	}
    31.  
    32. }

     Spboot04Application ：

    1. package com.ycx.spboot04;
    2.  
    3. import org.mybatis.spring.annotation.MapperScan;
    4. import org.springframework.boot.SpringApplication;
    5. import org.springframework.boot.autoconfigure.SpringBootApplication;
    6. import org.springframework.transaction.annotation.EnableTransactionManagement;
    7.  
    8. @MapperScan("com.ycx.spboot04.mapper")
    9. @EnableTransactionManagement
    10. @SpringBootApplication
    11. public class Spboot04Application {
    12.  
    13.     public static void main(String[] args) {
    14.         SpringApplication.run(Spboot04Application.class, args);
    15.     }
    16.  
    17. }

     前端页面处理：

    clzList.ftl：

    1. html>
    2. <html lang="en">
    3. <head>
    4.     <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
    5.     <link
    6.             href="https://cdn.bootcdn.net/ajax/libs/twitter-bootstrap/4.5.0/css/bootstrap.css"
    7.             rel="stylesheet">
    8.     <script
    9.             src="https://cdn.bootcdn.net/ajax/libs/twitter-bootstrap/4.5.0/js/bootstrap.js">script>
    10.     <title>班级列表title>
    11.     <style type="text/css">
    12.         .page-item input {
    13.             padding: 0;
    14.             width: 40px;
    15.             height: 100%;
    16.             text-align: center;
    17.             margin: 0 6px;
    18.         }
    19.  
    20.         .page-item input, .page-item b {
    21.             line-height: 38px;
    22.             float: left;
    23.             font-weight: 400;
    24.         }
    25.  
    26.         .page-item.go-input {
    27.             margin: 0 10px;
    28.         }
    29.     style>
    30. head>
    31. <body>
    32. <#include '/common.ftl'/>
    33. <#--查询的条件框-->
    34. <form class="form-inline"
    35.       action="${ctx }/clz/list" method="post">
    36.     <div class="form-group mb-2">
    37.         <input type="text" class="form-control-plaintext" name="cname"
    38.                placeholder="请输入班级名称">
    39.     div>
    40.     <button type="submit" class="btn btn-primary mb-2">查询button>
    41.     <a class="btn btn-primary mb-2" href="${ctx }/clz/toEdit">新增a>
    42. form>
    43.  
    44. <#--数据展示条-->
    45. <table class="table table-striped ">
    46.     <thead>
    47.     <tr>
    48.         <th scope="col">IDth>
    49.         <th scope="col">班级名称th>
    50.         <th scope="col">指导老师th>
    51.         <th scope="col">操作th>
    52.     tr>
    53.     thead>
    54.     <tbody>
    55.  
    56.         <#list lst as b>
    57.         <tr>
    58.             <td>${b.cid !}td>
    59.             <td>${b.cname !}td>
    60.             <td>${b.cteacher !}td>
    61.             <td>
    62.                 <a href="${ctx }/clz/toEdit?cid=${b.cid}">修改a>
    63.                 <a href="${ctx }/clz/del?cid=${b.cid}">删除a>
    64.             td>
    65.         tr>
    66.         
    67.     tbody>
    68. table>
    69. body>
    70. html>

    clzEdit.ftl：

    1. html>
    2. <html lang="en">
    3. <head>
    4.     <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
    5.     <title>编辑界面title>
    6. head>
    7. <body>
    8. <#include '/common.ftl' />
    9. <#if b??>
    10.     <#--修改-->
    11.     <form action="${ctx }/clz/edit" method="post">
    12.         cid:<input type="text" name="cid" value="${b.cid !}"><br>
    13.         cname:<input type="text" name="cname" value="${b.cname !}"><br>
    14.         cteacher:<input type="text" name="cteacher" value="${b.cteacher !}">span><br>
    15.         <input type="submit">
    16.     form>
    17.    <#else >
    18.     <#--新增-->
    19.        <form action="${ctx }/clz/add" method="post">
    20.            cid:<input type="text" name="cid" value=""><br>
    21.            cname:<input type="text" name="cname" value=""><br>
    22.            cteacher:<input type="text" name="cteacher" value=""><br>
    23.            <input type="submit">
    24.        form>
    26.  
    27. body>
    28. html>

    此时页面效果如下：

     删除了id为10 ：

     

     新增成功：

     

     

    为了检查方便，可以在yml文件里添加如下：

    1. logging:
    2.     level:
    3.         com.ycx.spboot04:debug

    接下来设置分页功能：

    用于Freemarker引擎生成分页条的工具类

    FreemarkerPageHelper .java：

    1. package com.ycx.spboot04.util;
    2.  
    3. import java.util.Map;
    4. import java.util.Set;
    5.  
    6. /**
    7.  * @author 杨总
    8.  * @create 2022-11-02 13:25
    9.  */
    10. public class FreemarkerPageHelper {
    11.     public static String toHTML(PageBean pageBean) {
    12.         StringBuffer sb = new StringBuffer();
    13. //		隐藏的form表单---这个就是上一次请求下次重新发的奥义所在
    14. //		上一次请求的URL
    15.         sb.append("
      ");
    16.         sb.append("	");
    17. //		上一次请求的参数
    18.         Map<String, String[]> paramMap = pageBean.getParamMap();
    19.         if(paramMap != null && paramMap.size() > 0) {
    20.             Set<Map.Entry<String, String[]>> entrySet = paramMap.entrySet();
    21.             for (Map.Entry<String, String[]> entry : entrySet) {
    22. //				参数名
    23.                 String key = entry.getKey();
    24. //				参数值
    25.                 for (String value : entry.getValue()) {
    26. //					上一次请求的参数，再一次组装成了新的Form表单
    27. //					注意：page参数每次都会提交，我们需要避免
    28.                     if(!"page".equals(key)) {
    29.                         sb.append("	");
    30.                     }
    31.                 }
    32.             }
    33.         }
    34.         sb.append("");
    35.  
    36. //		分页条
    37.         sb.append("
        ");
    38.         sb.append("	
    39. );
  • sb.append(" href='javascript:gotoPage(1)'>首页
    • ");
  • sb.append("
  • );
  • sb.append(" href='javascript:gotoPage("+pageBean.previousPage()+")'><
    • ");// less than 小于号
  • // sb.append("
  • 1
    • ");
  • // sb.append("
  • 2
    • ");
  • sb.append("
  • "+pageBean.getPage()+"
    • ");
  • sb.append("
  • >
    • ");
  • sb.append("
  • 尾页
    • ");
  • sb.append("
  • 到第);
  • sb.append(" type='text' id='skipPage' name='' />页
    • ");
  • sb.append("
  • );
  • sb.append(" href='javascript:skipPage()'>确定
    • ");
  • sb.append("
  • 共"+pageBean.getTotal()+"条
    • ");
  • sb.append("");
  • // 分页执行的JS代码
  • sb.append("");
  • return sb.toString();
  • }
  • }

    • 去controller添加： 

     还有clzList添加：

     运行效果 ：

    今日就分享到这里咯，再会！

  • 相关阅读:
    Python爬取阿里巴巴商城数据
    Windows安装Redis详细步骤
    Java泛型
    【生成模型】解决生成模型面对长尾类型物体时的问题 RE-IMAGEN: RETRIEVAL-AUGMENTED TEXT-TO-IMAGE GENERATOR
    38. 【Android教程】Handler 消息传递机制
    Databend使用入门
    经典电源电路基础（变压-整流-滤波-稳压）
    Monkey命令
    mysql8 添加一个用户 并给与所有权限 报错解决
    first()案例和take(n)案例_大数据培训课程
  • 原文地址：https://blog.csdn.net/weixin_65808248/article/details/127638261