向客户端返回JSON字符串有两种方法：

1.纯手工拼接：

result.append("{");

result.append("\"timu\":\""+timu+"\"");

result.append(",");

result.append("\"id\":\""+id3+"\"");

result.append("}");

2.引入jar包(jackson-all-1.7.6.jar)然后根据对象的get方法生成

package com.lhp.unit;

import java.io.IOException;

import java.util.Arrays;

import java.util.List;

import org.codehaus.jackson.JsonGenerationException;

import org.codehaus.jackson.annotate.JsonIgnore;

import org.codehaus.jackson.map.JsonMappingException;

import org.codehaus.jackson.map.ObjectMapper;

public class Customer

{

public Customer(String name, String age)

{

super();

this.name = name;

this.age = age;

}

private String name;

private String age;

public String getName()

{

return name;

}

public void setName(String name)

{

this.name = name;

}

public String getAge()

{

return age;

}

public void setAge(String age)

{

this.age = age;

}

public String getCity()

{

return "beijing";

}

@JsonIgnore

public String getBrith()

{

return "01-22";

}

public static void main(String[] args) throws JsonGenerationException, JsonMappingException, IOException

{

//1.导入jar包(jackson-all-1.7.6.jar)

//2.创建ObjectMapper对象

ObjectMapper mapper =new ObjectMapper();

//3.调用mapper的WriteValueAsString()方法把一个对象转化成json字符串

Customer customer=new Customer("李营", "20");

String jsonStr=mapper.writeValueAsString(customer);

System.out.println(jsonStr);

//4.注意：JakeSon对象使用get方法来定位JSON对象的属性

//5.通过添加注解(@JsonIgnore)来忽略某一个get定义的属性

//转集合：

List<Customer> customers = Arrays.asList(customer,new Customer("yue", "19"));

jsonStr = mapper.writeValueAsString(customers);

System.out.println(jsonStr);

}

}