将数据以json形式响应给前端

导jar包（依赖）

  <!-- JSON start-->
        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-core</artifactId>
            <version>2.12.6</version>
        </dependency>
        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-annotations</artifactId>
            <version>2.12.6</version>
        </dependency>
        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-databind</artifactId>
            <version>2.12.6</version>
        </dependency>
        <!-- JSON end  -->

配置springmvc.xml文件

<?xml version="1.0" encoding="UTF-8"?>

<beans
        xmlns="http://www.springframework.org/schema/beans"
        xmlns:context="http://www.springframework.org/schema/context"
        xmlns:aop="http://www.springframework.org/schema/aop"
        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xmlns:p="http://www.springframework.org/schema/p"
        xmlns:mvc="http://www.springframework.org/schema/mvc"
        xsi:schemaLocation="
		http://www.springframework.org/schema/beans
		http://www.springframework.org/schema/beans/spring-beans-4.3.xsd
		http://www.springframework.org/schema/mvc
        http://www.springframework.org/schema/mvc/spring-mvc-4.3.xsd
		http://www.springframework.org/schema/context
        http://www.springframework.org/schema/context/spring-context-4.3.xsd
		http://www.springframework.org/schema/aop
		http://www.springframework.org/schema/aop/spring-aop-4.3.xsd
		">
<!--开启mvc-->
    <mvc:annotation-driven />
<!--开启注解依赖-->
    <context:annotation-config></context:annotation-config>
    <!--自动扫描包-->
    <context:component-scan base-package="com.bh"></context:component-scan>

    <!-- 对view名称进行解析，给视图增加前缀和后缀 -->
    <!--    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver"-->
    <!--          p:prefix="/"-->
    <!--          p:suffix=".html"-->
    <!--    >-->
    <!--    </bean>-->

    <!--配置json的结果解析器 -->
    <bean class="org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter">
        <property name="cacheSeconds" value="0"/>
        <property name="messageConverters">
            <list>
                <bean class="org.springframework.http.converter.json.MappingJackson2HttpMessageConverter"/>
            </list>
        </property>
    </bean>

</beans>

User

package com.bh.po;

public class User {
    private String username;
    private String password;

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }
}

后端代码

package com.bh.controller;

import com.bh.po.User;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;

import java.util.ArrayList;
import java.util.List;
@Controller
public class JsonController {

//@ResponseBody注解的作用就是将数据转成json格式响应给前端

@RequestMapping("/json2.do")
public @ResponseBody List<User> getResult1() {
    List<User> list = new ArrayList<>();
    for (int i = 0; i < 10; i++) {
        User u = new User();
        u.setUsername("name_" + i);
        u.setPassword("pwd_" + i);

        list.add(u);
    }

    return list;
}
}

结果

[
	{
		"username":"name_0",
		"password":"pwd_0"
	},
	{
		"username":"name_1",
		"password":"pwd_1"
	},
	{
		"username":"name_2",
		"password":"pwd_2"
	},
	{
		"username":"name_3",
		"password":"pwd_3"
	},
	{
		"username":"name_4",
		"password":"pwd_4"
	},
	{
		"username":"name_5",
		"password":"pwd_5"
	},
	{
		"username":"name_6",
		"password":"pwd_6"
	},
	{
		"username":"name_7",
		"password":"pwd_7"
	},
	{
		"username":"name_8",
		"password":"pwd_8"
	},
	{
		"username":"name_9",
		"password":"pwd_9"
	}]