版本一: org.springframework.http.converter.json.MappingJacksonHttpMessageConverter
版本二:org.springframework.http.converter.json.MappingJackson2HttpMessageConverter
1、添加jackson.jar包
2、在applicationContext.xml配制文件中添加如下代码
org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter">
class="org.springframework.http.converter.json.MappingJackson2HttpMessageConverter "> text/html;charset=UTF-8
3、在controller中添加如下代码
@RequestMapping(value="/chinese/listTree", method = RequestMethod.POST)
@ResponseBody public List getlistChinese(Model model){ List list = (List) commonMgr.find("from User"); return list; }
返回值可以为list也可以为Map类型
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闲话少说,刚开始用SpringMVC, 页面要使用jQuery的ajax请求Controller。 但总是失败,主要表现为以下两个异常为:
异常一:Java.lang.ClassNotFoundException: org.springframework.http.converter.json.MappingJacksonHttpMessageConverter
异常二:SpringMVC @ResponseBody 415错误处理
网上分析原因很多,但找了很久都没解决,基本是以下几类:
springmvc添加配置、注解;
pom.xml添加jackson包引用;
Ajax请求时没有设置Content-Type为application/json
发送的请求内容不要转成JSON对象,直接发送JSON字符串即可
这些其实都没错!!!
以下是我分析的解决步骤方法:
(1)springMVC配置文件开启注解
< mvc:annotation-driven />
(2)添加springMVC需要添加如下配置。 (这个要注意spring版本,3.x和4.x配置不同 )
spring3.x是org.springframework.http.converter.json.MappingJacksonHttpMessageConverter
spring4.x是org.springframework.http.converter.json.MappingJackson2 HttpMessageConverter
具体可以查看spring-web的jar确认,哪个存在用哪个!
spring3.x配置:
< bean class = "org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter" >
< property name = "messageConverters" >
< list >
< ref bean = "jsonHttpMessageConverter" />
list >
property >
bean >
< bean id = "jsonHttpMessageConverter" class = "org.springframework.http.converter.json.MappingJacksonHttpMessageConverter" >
< property name = "supportedMediaTypes" >
< list >
< value > application/json; charset = UTF -8 value >
list >
property >
bean >
spring4.x配置:
< bean class = "org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter" >
< property name = "messageConverters" >
< list >
< ref bean = "jsonHttpMessageConverter" />
list >
property >
bean >
< bean id = "jsonHttpMessageConverter" class = "org.springframework.http.converter.json.MappingJackson2HttpMessageConverter" >
< property name = "supportedMediaTypes" >
< list >
< value > application/json; charset = UTF -8 value >
list >
property >
bean >
(3)pom.xml添加 jackson依赖 (这个要 注意spring版本,3.x和4.x配置不同 )
如果是spring 3.x,pom.xml添加如下配置
< dependency >
< groupId > org.codehaus.jackson groupId >
< artifactId > jackson-core-lgpl artifactId >
< version > 1.8.1 version >
dependency >
< dependency >
< groupId > org.codehaus.jackson groupId >
< artifactId > jackson-mapper-lgpl artifactId >
< version > 1.8.1 version >
dependency > span >
spring4.x, pom.xml添加如下配置
< dependency >
< groupId > com.fasterxml.jackson.core groupId >
< artifactId > jackson-core artifactId >
< version > 2.5.2 version >
dependency >
< dependency >
< groupId > com.fasterxml.jackson.core groupId >
< artifactId > jackson-databind artifactId >
< version > 2.5.2 version >
dependency >
这里要说明一下,spring3.x用的是org.codehaus.jackson的1.x版本,在maven资源库,已经不在维护,统一迁移到 com.fasterxml.jackson,版本对应为2.x
(4)ajax请求要求
dataType 为 json
contentType 为 'application/json;charse=UTF-8'
data 转JSON字符串
我的代码:如下: (注意:这里只是针对POST +JSON字符串形式请求 ,后面我会详细讲解不同形式请求,的处理方法和案例)
var data = {
userAccount: lock_username,
userPasswd:hex_md5(lock_password).toUpperCase()
}
$.ajax({
url : ctx + "/unlock.do",
type : "POST",
data : JSON.stringify(data),
dataType: 'json',
contentType:'application/json;charset = UTF -8',
success : function(result) {
console.log(result);
}
});
(5) Controller 接收响应JSON
以上配置OK,Controller中使用JSON方式有多种。这里简单介绍几种。
这个关键在于ajax请求是将数据以什么形式传递到后台,这里我总结了三种形式
POST + JSON字符串形式
POST + JSON对象形式
GET + 参数字符串
方式一: POST + JSON字符串形式,如下:
var data = {
userAccount: lock_username,
userPasswd:hex_md5(lock_password).toUpperCase()
}
$.ajax({
url : ctx + "/unlock.do" ,
type : "POST" ,
data : JSON.stringify(data),
dataType: 'json' ,
contentType:'application/json;charset=UTF-8' ,
success : function (result) {
console.log(result);
}
});
ar data = {
userAccount: lock_username,
userPasswd:hex_md5(lock_password).toUpperCase()
}
$.ajax({
url : ctx + "/unlock.do" ,
type : "POST" ,
data : data,
dataType: 'json' ,
success : function (result) {
console.log(result);
}
});
代码案例:
5-1: 使用@RequestBody来设置输入 ,@ResponseBody设置输出 (POST + JSON字符串形式 )
JS请求:
var data = {
userAccount: lock_username,
userPasswd:hex_md5(lock_password).toUpperCase()
}
$.ajax({
url : ctx + "/unlock.do" ,
type : "POST" ,
data : JSON.stringify(data),
dataType: 'json' ,
contentType:'application/json;charset=UTF-8' ,
success : function (result) {
console.log(result);
}
});
Controller处理:
@RequestMapping (value = "/unlock" , method = RequestMethod.POST,consumes = "application/json" )
@ResponseBody
public Object unlock( @RequestBody User user) {
JSONObject jsonObject = new JSONObject();
try {
Assert.notNull(user.getUserAccount(), "解锁账号为空" );
Assert.notNull(user.getUserPasswd(), "解锁密码为空" );
User currentLoginUser = (User) MvcUtils.getSessionAttribute(Constants.LOGIN_USER);
Assert.notNull(currentLoginUser, "登录用户已过期,请重新登录!" );
Assert.isTrue(StringUtils.equals(user.getUserAccount(),currentLoginUser.getUserAccount()), "解锁账号错误" );
Assert.isTrue(StringUtils.equalsIgnoreCase(user.getUserPasswd(),currentLoginUser.getUserPasswd()), "解锁密码错误" );
jsonObject.put("message" , "解锁成功" );
jsonObject.put("status" , "success" );
}catch (Exception ex){
jsonObject.put("message" , ex.getMessage());
jsonObject.put("status" , "error" );
}
return jsonObject;
}
5-2: 使用HttpEntity来实现输入绑定,来 ResponseEntit 输出绑定( POST + JSON字符串形式 )
JS请求:
var data = {
userAccount: lock_username,
userPasswd:hex_md5(lock_password).toUpperCase()
}
$.ajax({
url : ctx + "/unlock.do" ,
type : "POST" ,
data : JSON.stringify(data),
dataType: 'json' ,
contentType:'application/json;charset=UTF-8' ,
success : function (result) {
console.log(result);
}
});
Controller处理:
@RequestMapping (value = "/unlock" , method = RequestMethod.POST,consumes = "application/json" )
public ResponseEntity unlock(HttpEntity user) {
JSONObject jsonObject = new JSONObject();
try {
Assert.notNull(user.getBody().getUserAccount(), "解锁账号为空" );
Assert.notNull(user.getBody().getUserPasswd(), "解锁密码为空" );
User currentLoginUser = (User) MvcUtils.getSessionAttribute(Constants.LOGIN_USER);
Assert.notNull(currentLoginUser, "登录用户已过期,请重新登录!" );
Assert.isTrue(StringUtils.equals(user.getBody().getUserAccount(),currentLoginUser.getUserAccount()), "解锁账号错误" );
Assert.isTrue(StringUtils.equalsIgnoreCase(user.getBody().getUserPasswd(),currentLoginUser.getUserPasswd()), "解锁密码错误" );
jsonObject.put("message" , "解锁成功" );
jsonObject.put("status" , "success" );
}catch (Exception ex){
jsonObject.put("message" , ex.getMessage());
jsonObject.put("status" , "error" );
}
ResponseEntity responseResult = new ResponseEntity(jsonObject,HttpStatus.OK);
return responseResult;
}
5-3: 使用request.getParameter获取请求参数,响应JSON( POST + JSON对象形式 ) 和( GET + 参数字符串 ),Controller处理一样,区别在于是否加注解 method ,
如果不加适用GET + POST ;
如果 method= RequestMethod.POST,用于POST 请求;
如果method=RequestMethod.GET,用于GET请求;
POST+ JSON对象形式请求:
var data = {
userAccount: lock_username,
userPasswd:hex_md5(lock_password).toUpperCase()
}
$.ajax({
url : ctx + "/unlock.do" ,
type : "POST" ,
data : data,
dataType: 'json' ,
success : function (result) {
console.log(result);
}
});
GET + 参数字符串请求:
$.ajax({
url : ctx + "/unlock.do" ,
type : "GET" ,
dataType: "text" ,
data : "userAccount=" +lock_username+ "&userPasswd=" + hex_md5(lock_password).toUpperCase(),
success : function (result) {
console.log(result);
}
});
Controller处理:
@RequestMapping (value = "/unlock" )
public void unlock(HttpServletRequest request,HttpServletResponse response) throws IOException {
JSONObject jsonObject = new JSONObject();
String userAccount = (String)request.getParameter("userAccount" );
String userPasswd = (String)request.getParameter("userPasswd" );
try {
Assert.notNull(userAccount, "解锁账号为空" );
Assert.notNull(userPasswd, "解锁密码为空" );
User currentLoginUser = (User) MvcUtils.getSessionAttribute(Constants.LOGIN_USER);
Assert.notNull(currentLoginUser, "登录用户已过期,请重新登录!" );
Assert.isTrue(StringUtils.equals(userAccount,currentLoginUser.getUserAccount()), "解锁账号错误" );
Assert.isTrue(StringUtils.equalsIgnoreCase(userPasswd,currentLoginUser.getUserPasswd()), "解锁密码错误" );
jsonObject.put("message" , "解锁成功" );
jsonObject.put("status" , "success" );
}catch (Exception ex){
jsonObject.put("message" , ex.getMessage());
jsonObject.put("status" , "error" );
}
response.getWriter().print(jsonObject.toString());
}
5-4: 使用@ModelAttribute将参数封装对象, 响应JSON( POST + JSON对象形式) 和( GET + 参数字符串 ),Controller处理一样,区别在于是否加注解 method 。
如果不加适用GET + POST ;
如果 method= RequestMethod.POST,用于POST 请求;
如果method=RequestMethod.GET,用于GET请求;
POST+ JSON对象形式请求:
var data = {
userAccount: lock_username,
userPasswd:hex_md5(lock_password).toUpperCase()
}
$.ajax({
url : ctx + "/unlock.do" ,
type : "POST" ,
data : data,
dataType: 'json' ,
success : function (result) {
console.log(result);
}
});
GET + 参数字符串请求:
$.ajax({
url : ctx + "/unlock.do" ,
type : "GET" ,
dataType: "text" ,
data : "userAccount=" +lock_username+ "&userPasswd=" + hex_md5(lock_password).toUpperCase(),
success : function (result) {
console.log(result);
}
});
Controller处理:(这个案例只支持POST)
@RequestMapping (value = "/unlock" ,method = RequestMethod.POST)
public void unlock( @ModelAttribute ( "user" ) User user,PrintWriter printWriter) throws IOException {
JSONObject jsonObject = new JSONObject();
try {
Assert.notNull(user.getUserAccount(), "解锁账号为空" );
Assert.notNull(user.getUserPasswd(), "解锁密码为空" );
User currentLoginUser = (User) MvcUtils.getSessionAttribute(Constants.LOGIN_USER);
Assert.notNull(currentLoginUser, "登录用户已过期,请重新登录!" );
Assert.isTrue(StringUtils.equals(user.getUserAccount(),currentLoginUser.getUserAccount()), "解锁账号错误" );
Assert.isTrue(StringUtils.equalsIgnoreCase(user.getUserPasswd(),currentLoginUser.getUserPasswd()), "解锁密码错误" );
jsonObject.put("message" , "解锁成功" );
jsonObject.put("status" , "success" );
}catch (Exception ex){
jsonObject.put("message" , ex.getMessage());
jsonObject.put("status" , "error" );
}
printWriter.print(jsonObject.toString());
}
寻找问题学习过程中参考资料:
Spring MVC 学习笔记 json格式的输入和输出
帮我找到解决异常问题的国外论坛贴