Jackson 高性能的JSON處理 ObjectMapper
Jackson能夠輕鬆的將Java對象轉換成json對象和xml文檔，一樣也能夠將json、xml轉換成Java對象。java
一、 下載依賴庫jar包json
Jackson的jar all下載地址：http://jackson.codehaus.org/1.7.6/jackson-all-1.7.6.jarapi
而後在工程中導入這個jar包便可開始工做數組
官方示例：http://wiki.fasterxml.com/JacksonInFiveMinutesapp
由於下面的程序是用junit測試用例運行的，因此還得添加junit的jar包。版本是junit-4.2.8ide
若是你須要轉換xml，那麼還須要stax2-api.jar測試
二、 測試類基本代碼以下ui
package jackJson.test.pojo;
public class Student {
private Integer uid;
private String uname;
private String upwd;
private Integer number;
private Boolean isstudent;
public Integer getUid() {
return uid;
}
public void setUid(Integer uid) {
this.uid = uid;
}
public String getUname() {
return uname;
}
public void setUname(String uname) {
this.uname = uname;
}
public String getUpwd() {
return upwd;
}
public void setUpwd(String upwd) {
this.upwd = upwd;
}
public Integer getNumber() {
return number;
}
public void setNumber(Integer number) {
this.number = number;
}
public Boolean getIsstudent() {
return isstudent;
}
public void setIsstudent(Boolean isstudent) {
this.isstudent = isstudent;
}
@Override
public String toString() {
return "Student [uid=" + uid + ", uname=" + uname + ", upwd=" + upwd
+ ", number=" + number + ", isstudent=" + isstudent + "]";
}
}
package jackJson.test;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import java.util.Set;
import jackJson.test.pojo.Student;
import com.fasterxml.jackson.core.JsonGenerator;
import com.fasterxml.jackson.core.JsonParseException;
import com.fasterxml.jackson.databind.JsonMappingException;
import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.SerializationConfig;
public class Jackson {
public static JsonGenerator jsonGenerator = null;
private static ObjectMapper mapper = new ObjectMapper();
public static void main(String[] args) {
Student student = new Student();
student.setIsstudent(true);
student.setUid(1000);
student.setUname("xiao liao");
student.setUpwd("123");
student.setNumber(12);
Map<String, Student> stuMap = new HashMap<String, Student>();
stuMap.put("1", student);
stuMap.put("2", student);
List<Object> stuList = new ArrayList<Object>();
List<Student> stuList1 = new ArrayList<Student>();
stuList1.add(student);
student= new Student();
student.setIsstudent(false);
student.setUid(200);
student.setUname("xiao mi");
stuList1.add(student);
stuList.add(student);
stuList.add("xiao xin");
stuList.add("xiao er");
stuList.add(stuMap);
//readJson2List();
//readJson2Array();
try {
writeEntity2Json(student);
//writeJson2Entity();
//writeList2Json(stuList1);
//writeJson2List();
//writeArray2Json(array);
//writeMap2Json(stuMap);
} catch (IOException e) {
e.printStackTrace();
}
}
/**
*
* <code>writeEntity2Json</code>
* @description: TODO(實體類轉換成json)
* @param object
* @throws IOException
* @since
*/
public static void writeEntity2Json(Object object) throws IOException {
mapper.writeValue( new File("D:\\developSoft\\aaadowload\\testjson1\\lib\\aa.txt"),object );
mapper.writeValue( System.out,object );
}
/**
*
* <code>writeJson2Entity</code>
* @description: TODO(json轉換成實體)
* @throws IOException
* @since
*/
public static void writeJson2Entity() throws IOException {
System.out.println("json串轉換成entity-------------");
// File file = new File("D:\\developSoft\\aaadowload\\testjson1\\lib\\aa.txt");
// FileInputStream inputStream = new FileInputStream(file);
// Student student = mapper.readValue(inputStream,Student.class);
// System.out.println(student.toString());
//漂亮輸出
//mapper.defaultPrettyPrintingWriter().writeValueAsString(value);
String json = "{\"uid\":1000,\"uname\":\"xiao liao\",\"upwd\":\"123\",\"number\":12.0,\"isstudent\":true}";
Student student1 = mapper.readValue(json,Student.class);
System.out.println("json2:"+student1.toString());
}
/**
*
* <code>writeList2Json</code>
* @description: TODO(list轉換成json)
* @param object
* @throws IOException
* @since
*/
public static void writeList2Json(Object object) throws IOException {
System.out.println("==>"+mapper.writeValueAsString(object));
mapper.writeValue( new File("D:\\developSoft\\aaadowload\\testjson1\\lib\\aamap.txt"),object );
mapper.writeValue( System.out , object );
}
/**
*
* <code>writeJson2List</code>
* @description: TODO(json專程list對象)
* @throws IOException
* @since
*/
public static void writeJson2List() throws IOException {
System.out.println("json串轉換成entity-------------");
File file = new File("D:\\developSoft\\aaadowload\\testjson1\\lib\\aa.txt");
FileInputStream inputStream = new FileInputStream(file);
Student student = mapper.readValue(inputStream,Student.class);
System.out.println(student.toString());
String json = "[{\"uid\":1000,\"uname\":\"xiao liao\",\"upwd\":\"123\",\"number\":12.0,\"isstudent\":true},{\"uid\":200,\"uname\":\"xiao mi\",\"upwd\":null,\"number\":0.0,\"isstudent\":false}]";
List<LinkedHashMap<String, Object>> s= mapper.readValue(json,List.class);
for (int i = 0; i < s.size(); i++) {
LinkedHashMap<String, Object> link = s.get(i);
Set<String> key = link.keySet();
for (Iterator iterator = key.iterator(); iterator.hasNext();) {
String string = (String) iterator.next();
System.out.println(string+"==>"+link.get(string));
}
System.out.println("json:"+i+""+s.get(i).toString());
}
}
/**
*
* <code>writeArray2Json</code>
* @description: TODO(數組轉換成json)
* @param object
* @throws IOException
* @since
*/
public static void writeArray2Json(Object object) throws IOException {
// writeValue具備和writeObject相同的功能
mapper.writeValue( new File("D:\\developSoft\\aaadowload\\testjson1\\lib\\aa.txt"),object );
mapper.writeValue(System.out,object );
}
/**
*
* <code>writeMap2Json</code>
* @description: TODO(map對象轉換成json對象)
* @param object
* @throws IOException
* @since
*/
public static void writeMap2Json(Object object) throws IOException {
System.out.println("使用ObjectMapper-----------");
// writeValue具備和writeObject相同的功能
System.out.println("==>"+mapper.writeValueAsString(object));
mapper.writeValue( new File("D:\\developSoft\\aaadowload\\testjson1\\lib\\aamap.txt"),object );
mapper.writeValue( System.out , object );
}
/**
* JSON轉換爲List對象
*/
public static void readJson2List() {
String json = "[{\"uid\":1,\"uname\":\"www\",\"number\":234,\"upwd\":\"456\"},"
+ "{\"uid\":5,\"uname\":\"tom\",\"number\":3.44,\"upwd\":\"123\"}]";
try {
List<LinkedHashMap<String, Object>> list = mapper.readValue(json, List.class);
System.out.println(list.size());
for (int i = 0; i < list.size(); i++) {
Map<String, Object> map = list.get(i);
Set<String> set = map.keySet();
for (Iterator<String> it = set.iterator(); it.hasNext();) {
String key = it.next();
System.out.println(key + ":" + map.get(key));
}
}
} catch (JsonParseException e) {
e.printStackTrace();
} catch (JsonMappingException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
/**
* JSON轉換爲List對象
*/
public static void readJson2Array() {
String json = "[{\"uid\":1,\"uname\":\"www\",\"number\":234,\"upwd\":\"456\"},"
+ "{\"uid\":5,\"uname\":\"tom\",\"number\":3.44,\"upwd\":\"123\"}]";
try {
Student[] students = mapper.readValue(json, Student[].class);
for (Student student : students) {
System.out.println(">"+student.toString());
}
} catch (JsonParseException e) {
e.printStackTrace();
} catch (JsonMappingException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
}
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