Jackson.jar的使用记录
之前一直使用json-lib.jar,近期发现网上说这个jackson.jar比較好
package com.spring.controller;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.codehaus.jackson.JsonEncoding;
import org.codehaus.jackson.JsonGenerator;
import org.codehaus.jackson.map.ObjectMapper;
import org.codehaus.jackson.map.ObjectWriter;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.servlet.ModelAndView;
@Controller
public class JacksonController {
@RequestMapping(value="user/jackson", method = {RequestMethod.POST,RequestMethod.GET})
public ModelAndView PostJsonTest(HttpServletRequest request,HttpServletResponse response) throws IOException{
ModelAndView mav=new ModelAndView();
mav.addObject("time", new Date());
JsonGenerator jsonGenerator = null;
ObjectMapper objectMapper = new ObjectMapper();
jsonGenerator = objectMapper.getJsonFactory().createJsonGenerator(System.out, JsonEncoding.UTF8);
//将java对象转为json
UserJson userJson=new UserJson();
userJson.setUsername("小米");
userJson.setId("31231");
userJson.setPwd("123456");
userJson.setAge(24);
userJson.setAddress("广州");
userJson.setTel(13676586);
//objectMapper.writeValue(jsonGenerator, userJson);
String jsonStr = objectMapper.writeValueAsString(userJson);
//writeObject能够转换java对象，eg:JavaBean/Map/List/Array等
//jsonGenerator.writeObject(userJson);
System.out.println("-----json-------");
String jsonSS="{\"address\":\"广州\",\"id\":\"31231\",\"username\":\"小米\",\"tel\":13676586,\"age\":24,\"pwd\":\"123456\"}";
System.out.println("--------字符串json-------"+jsonSS);
System.out.println("------标准jsonStr--------"+jsonStr);
mav.addObject("jsonStr", jsonStr);
mav.addObject("jsonss", jsonSS.toString());
mav.setViewName("json/jackson");
//将list集合转为json
List<UserJson> list=new ArrayList<UserJson>();
for(int i=0;i<5;i++){
UserJson u3=new UserJson();
u3.setId("ooo"+i);
u3.setUsername("小小明"+i);
u3.setPwd("123456"+i);
u3.setAge(20+i);
u3.setAddress("广州"+i);
u3.setTel(13664+i*i*i);
list.add(u3);
}
String jsonlist = objectMapper.writeValueAsString(list);
mav.addObject("jsonlist", jsonlist.toString());
mav.setViewName("json/jackson");
return mav;
}
/**
* list转为json数组
*/
public String writeListToJsonArray() throws IOException {
/*List<Event> list = new ArrayList<Event>(2);
list.add(new Event("a1","a2"));
list.add(new Event("b1","b2"));*/
List<String> list = new ArrayList<String>();
list.add("A2");
list.add("B2");
OutputStream out = new ByteArrayOutputStream();
ObjectMapper mapper = new ObjectMapper();
mapper.writeValue(out, list);
byte[] data = ((ByteArrayOutputStream) out).toByteArray();
System.out.println(new String(data));
String result=new String(data);
return result;
}
/**
* list转为json数组
*/
public String writeListToJsonArray2() throws IOException {
ObjectWriter ow = new ObjectMapper().writer().withDefaultPrettyPrinter();
final ObjectMapper mapper = new ObjectMapper();
List<String> list = new ArrayList<String>();
list.add("A2");
list.add("B2");
String jsonArray = ow.writeValueAsString(list);
System.out.println(jsonArray);
return jsonArray;
}
}
///java对象
class UserJson{
private String id;
private String username;
private String pwd;
private Integer age;
private int tel;
private String address;
public String getId() {
return id;
}
public void setId(String id) {
this.id = id;
}
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}
public String getPwd() {
return pwd;
}
public void setPwd(String pwd) {
this.pwd = pwd;
}
public Integer getAge() {
return age;
}
public void setAge(Integer age) {
this.age = age;
}
public int getTel() {
return tel;
}
public void setTel(int tel) {
this.tel = tel;
}
public String getAddress() {
return address;
}
public void setAddress(String address) {
this.address = address;
}
}
list转为json数组（是Java main程序）
package com.main.java.demo;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.util.ArrayList;
import java.util.List;
import org.codehaus.jackson.map.ObjectMapper;
import org.codehaus.jackson.map.ObjectWriter;
public class JacksonDemo {
public static void main(String args[]) throws IOException{
//writeListToJsonArray();
//writeListToJsonArray2();
//writeListToJsonArray3();
//writeListToJsonArray4();
//writeListToJsonArray5();
writeListToJsonArray6();
}
/**
* list转为json数组
*/
public static String writeListToJsonArray() throws IOException {
/*List<Event> list = new ArrayList<Event>(2);
list.add(new Event("a1","a2"));
list.add(new Event("b1","b2"));*/
/*List<String> list = new ArrayList<String>();
list.add("A2");
list.add("B2");*/
/*List<Integer> list = new ArrayList<Integer>();
list.add(12);
list.add(45);
list.add(5);*/
List<Float> list = new ArrayList<Float>();
list.add((float) 12.32);
list.add((float) 45.12);
list.add((float) 5.09);
OutputStream out = new ByteArrayOutputStream();
ObjectMapper mapper = new ObjectMapper();
mapper.writeValue(out, list);
byte[] data = ((ByteArrayOutputStream) out).toByteArray();
System.out.println(new String(data));
String result=new String(data);
return result;
}
/**
* list转为json数组
*/
public static String writeListToJsonArray2() throws IOException {
ObjectWriter ow = new ObjectMapper().writer().withDefaultPrettyPrinter();
final ObjectMapper mapper = new ObjectMapper();
List<String> list = new ArrayList<String>();
list.add("A2");
list.add("B2");
//// Using writeValueAsString
String jsonArray = ow.writeValueAsString(list);
System.out.println(jsonArray);
return jsonArray;
}
/**
* list转为json数组
*/
public static String writeListToJsonArray3() throws IOException {
ObjectWriter ow = new ObjectMapper().writer().withDefaultPrettyPrinter();
ObjectMapper mapper = new ObjectMapper();
List<String> list = new ArrayList<String>();
list.add("A23");
list.add("B23");
//// Using Bytes
byte[] data = mapper.writeValueAsBytes(list);
String jsonArray = new String(data, "UTF-8");
System.out.println(jsonArray);
return jsonArray;
}
/**
* list转为json数组
*/
public static String writeListToJsonArray4() throws IOException {
ObjectWriter ow = new ObjectMapper().writer().withDefaultPrettyPrinter();
ObjectMapper mapper = new ObjectMapper();
List<String> list = new ArrayList<String>();
list.add("A234");
list.add("B234");
// Using ByteArrayOutputStream with new String()
OutputStream os = new ByteArrayOutputStream();
mapper.writeValue(os, list);
byte[] data = ((ByteArrayOutputStream) os).toByteArray();
String jsonArray = new String(data, "UTF-8");
System.out.println(jsonArray);
return jsonArray;
}
/**
* list转为json数组
*/
public static String writeListToJsonArray5() throws IOException {
ObjectWriter ow = new ObjectMapper().writer().withDefaultPrettyPrinter();
ObjectMapper mapper = new ObjectMapper();
List<String> list = new ArrayList<String>();
list.add("A2345");
list.add("B2345");
// Using ByteArrayOutputStream
final OutputStream os = new ByteArrayOutputStream();
mapper.writeValue(os, list);
String jsonArray = ((ByteArrayOutputStream) os).toString("UTF-8");
System.out.println(jsonArray);
return jsonArray;
}
/**
* list转为json数组
*/
public static String writeListToJsonArray6() throws IOException {
ObjectWriter ow = new ObjectMapper().writer().withDefaultPrettyPrinter();
ObjectMapper mapper = new ObjectMapper();
List<String> list = new ArrayList<String>();
list.add("A23456");
list.add("B23456");
// Using writeValueAsString
String jsonArray = mapper.writeValueAsString(list);
System.out.println(jsonArray);
return jsonArray;
}
}
jsp页面：